It is asserted in the theses Lundbäck S., “Cardiac Pumping and Function of the Ventricular Septum”, Stockholm, 1986 that the pumping and regulation of the human heart take place in a manner which is at variance with the prevalent view.
According to the cited publication, the healthy heart performs its pumping action without substantially changing its outer contours and volumes.
As a result of the theory presented in the above-mentioned publication regarding the heart's pumping and regulating function a new class of pumps has emerged, a so called dynamic displacement pump or delta (Δ) volume pump (abbreviated as ΔV-pump).
The principles of a ΔV-pump will now be described with references to FIGS. 1a and 1b. The pump comprises an upper cylinder 2 with diameter d1 and a lower cylinder 4 with diameter d2, where d2>d1. These two cylinders are connected to each other via a third cylinder 6 that is freely movably arranged between the upper and lower cylinders. The movable cylinder 6 is provided with a valve 8 at its lowest part that corresponds e.g. to the Mitral valve in the heart. The volume above this valve is defined as the atrial volume (Va) and the volume below the valve is defined as the ventricular volume (Vv). The lower cylinder is provided with an outflow valve 10 at its lowest part that corresponds e.g. to the aortic valve in the heart. As can be seen from FIG. 1b is a ring-shaped cylindrical volume gradually obtained between the movable cylinder and the inner wall of the lower cylinder when the movable cylinder is moved down, ΔV in the figure. This results in that the volume Va+Vv decreases with the volume ΔV when the movable cylinder moves between its upper position and its lower position.
A source of energy (not shown in the figures) is adapted to move the movable cylinder from its upper position to its lower position, which defines the length L of a stroke for the pump. When the movable cylinder moves down to its lowest position the outflow valve is forced to open and a part of volume Vv is expelled. The movable cylinder is then released from the source of energy and can return to its upper position by hydraulic forces created by pressure gradients if there is an inflow to the pump. This is referred to the DeltaV-function (ΔV-function). If Av and Aa designates the cross-sectional areas of the upper and lower cylinder, respectively, ΔV equals L(Av-Aa).
WO-01/88642 relates to a computer based system adapted to create a representation of the pumping action of a heart by using a mathematical model of the functions of the heart based upon the above-described principles of the ΔV-pump in order to make it possible to enhance the methods of analyses, diagnosis and therapy of the heart. The heart is modelled by a computer-based representation of one dynamic displacement pump or of two interconnected dynamic displacement pumps, ΔV-pumps.
Many different requirements, boundary conditions, must generally be met when implementing a mathematical model on to a pump, describing its construction, power source, pumping and regulating functions in a circulatory system. There will be even more boundary conditions if the circulatory system comprises two circulatory systems, as is the case with the heart, and pumps, where the flow to and from the two circulatory systems always shall be in balance.
Usually individual's heart and circulatory system are investigated at rest when flow, frequencies and inotropic stimuli are low. Most of all reference values telling if the heart and the circulatory system is in a good or bad position are found and compared during idling pumping motions of the heart. During these circumstances the energy to mechanical converting, characteristics of the DeltaV-principles are less pronounced for the pumping, filling and regulating functions of the heart. This may be one of the reasons why the squeezing pumping functions of the heart together with the regulating functions of the “Frank-Starling law” as a lost motion squeezing displacement pump, still exists as a platform for heart and circulatory diagnostics of today.
New investigating methods like MRI (Magnetic Resonance Imaging) and Spin CT (Spinning Computer aided Tomography), and further developments within the ultra sound technique with TVI (Tissue Velocity Imaging) and reflector based velocity imaging (2D strain) with reduced visualization of false movements, is showing that the heart is pumping with longitudinal motions of an AV (Atria-Ventricular)-plane together with squeezing motions of the muscles. The AV-plane is defined as the orifice of the mitral ring at the left ventricle and correspondingly the orifice of the tricuspid valve will serve as an AV-plane for the right ventricle. The functions of the right ventricle are very seldom discussed. The true area of the spherical piston and the DeltaV-functions are not yet understood, even though heavy discussions have started to explain what kind of forces there are acting on the ventricular filling. Terms like Diastolic heart failure have become a popular scientific discussion subject. What gives the heart its regulating functions within the new insight of a piston like pumping function has not yet become a discussion subject.
Investigations of the heart with old or new investigating methods bring a lot of information that may be very hard to interpret. Every mechanical device can be expressed in state diagrams if the mechanics behind the working principles are fully known. That is not the case concerning the heart as a mechanical device. The filling and regulating functions of the heart has been debated during centuries. The complex architecture and motions of the heart together with unknown mechanics, makes it almost impossible to determine the contributions of different activities and functions within the heart even at very low flow and heart rates. At higher flow and heart rates, all investigating methods, more or less, shows a chaotic output of information. This, together with the general belief that the heart is pumping with squeezing functions, are probably the reasons why activities of the heart muscle cells have been in focus in trying to understand and analyze the functions of the heart.
The general object of the present invention is to create a system that by processing means in various kinds of investigating methods can be used in one, two or three dimensions to register, analyze, validate, present, simulate and communicate the functions of the heart as a cluster state machine and optionally the circulatory system including the coronary system down to molecular levels This would in a substantial way improve the knowledge about the pumping and regulating functions of the heart and create better and faster diagnostic and therapeutic tools and methods.